Influence of Outdoor Particulate Matter on Indoor Air Quality and Human Health Risks in Urban High-Rise Buildings

Urban areas are largely exposed to the penetration of outdoor particulate matter (PM) indoors, degrading indoor air quality (IAQ) and causing significant human health risks. This work evaluates the impact of outdoor-generated PM on IAQ in a high-rise residential building, keeping windows open and closed under controlled conditions. Real-time monitoring was conducted to assess PM levels and vertical variations, while respiratory deposition dose (RDD) and health risk (HR) were estimated across four demographic groups. Morphological and chemical characterization of PM was also performed. Results reflected higher PM concentrations on upper floors than lower ones, with peaks during morning and evening traffic hours. Indoor PM levels decreased notably when windows were closed, proving as an effective mitigation measure. RDD was higher in men due to greater tidal volume, while HR was lowest for children aged 8-10 years, possibly due to their better immune system. PM particles exhibited spherical, clustered, and irregular morphologies, mainly containing Na, Al, Si, C, K, and Ca, with trace Barium from vehicular emissions. These findings indicate the need for effective urban air quality management and mitigation strategies to reduce indoor human exposure to traffic-related PM.